A conventionally known lens barrel includes: a cam drum having a cam groove, a lens holding frame holding a moving lens group; and a cam follower installed on the outer periphery of the lens holding frame, wherein the lens holding frame moves in the axial direction of the cam drum by the cam follower movably engaging with a groove side wall of the cam groove and moving along the cam groove. In this lens barrel using a cam driving mechanism as above, the lens holding frame backlashes upon zooming due to a slight gap between the cam follower and the cam groove, for example, and an image wobbling occurs. Furthermore with the increased number of pixels and the reduced size of the image sensor of the video camera, digital camera and the like in recent years, the optical performance of each lens is becoming more sensitive in a zoom lens, and a slight backlashing of the lens holding frame upon zooming influences the decline of the imaging performance.
An available technology to prevent the backlashing of the lens holding frame upon zooming is a technology disclosed in Japanese Examined Utility Model Application Publication No. H2-44247. According to this technology, the cam follower is formed of two members (cam pins) having a tapered portion at the tip, where the outer periphery of one of the members is inter-fitted with an inter-fit concave portion formed on the other member, and the cam follower is pressed by V-shaped cam grooves created in the fixed drum and the cam drum respectively, by a spring biasing outward in a radial direction.
In the case of the technology disclosed in Japanese Examined Utility Model Application Publication No. H2-44247, however, the two cam followers inter-fit, therefore the lens holding frame could incline by the backlash generated in the cam follower radial direction, that is, the cam drum axial direction, due to the dimensional difference between the diameters of the two cam followers.